Fuel oil sludge dispersant compositions

ABSTRACT

Sludges which normally form in fuel oils are maintained in a suspended state by the addition of a sludge dispersant comprising a mixture of monoethanol amine salts of dialkyl/monoalkyl orthophosphoric acid derived from aliphatic alcohols having from 10 - 20 carbon atoms.

United States Patent 1191 Adams 1 1 Oct. 2, 1973 [22] Filed:

[ 41 FUEL 01L SLUDGE DISPERSANT COMPOSITIONS [75] Inventor: Alan Douglas Adams, Newark, Del.

[73] Assignee: Atlas Chemical lndustries,lnc.,

Wilmington, Del.

' Dec. 24, 1970 21 Appl. No.: 101,432

[52] US. Cl 44/72, 44/DIG. 4, 252/325 [51] Int. Cl Cl0| 1/26 [58] Field 01' Search 252/325; 44/72,

[56] References Cited UNITED 1 STATES PATENTS 9/1959 Clarke et a1. 44/72 9/1959 Gottshall 44/72 3,484,375 12/1969 Hu 44/72 3,542,679 11/1970 Cyba.... 252/325 3,600,470 8/1971 Lewis 252/325 2,988,434 6/1961 Gottshall et a1. 44/72 6/1967 Popkin 44/72 Primary Examiner-Daniel E. Wyman Assistant Examiner-4. Vaughn Attorney-Kenneth E. Mulford and Roger R. Horton [57] ABSTRACT 8 Claims, No Drawings FUEL OIL SLUDGE DISPERSANT COMPOSITIONS This invention relates to distillate fuel oil additive compositions and mixtures containing straight-run fuel oils which if untreated gradually oxidize or otherwise decompose during storage to form insoluble sludge and sediment which are often responsible for the subsequent clogging of fuel lines, filters, and passageways in engines and burner systems through which such fuels pass. When such plugging occurs, the system ceases to operate or reduces operating efficiency to the point where the engine or burner must be shut down for cleaning.

Another problem which arises from storage of fuel oils is the accumulation of moisture from the air which enters the tank and condenses to form an aqueous layer which if emulsified with the oil may cause rusting and corrosion of fuel lines, engines, nozzles, and other associated equipment.

The deterioration of distillate fuel oils on storage and the subsequent formation of both soluble and insoluble residue has been recognized for sometime, but the mechanism by which these sludges are formed is not clearly understood. it is believed, however, to be associated with oxidation and the polymerization of free radicals that are thereby formed. incorporation of antioxidants is not successful in stabilizing the fuel oil fraction of petroleum distillate as it is in others such as gasolines, greases, lubricating oils, or in rubber products.

Additives such as esterified ethanol ammonium phosphate salts described in U. S. Pat. No. 2,574,954 and U. S. Pat. No. 3,574,955; tetraalkyl ammonium salts of an alkyl polyalkyleneoxy ester of phosphoric acid such as described in U. S. Pat. No. 2,904,416 or aliphatic ammonium salts of dialkyl orthophosphoric acid such as described in U; S. Pat. No. 2,905,541 have not proven to be completely satisfactory for one reason or another.

it is the primary object of the invention to provide a process for treating fuel oils such that sludge forming materials are maintained in suspension.

It is also the object of the present invention to provide an improved phosphate additive-petroleum distillate composition which when incorporated at high dilution with petroleum distillate fuel oils overcomes all the fered by the additives of this invention is that they burn clean and leave no ash deposit within the burner.

The sludge dispersant and stabilizing materials of this invention comprise a mixture of monoethanol ammonium phosphate salts having the general formula:

R0), PO (ON n,,cH2cH-,om

wherein R is an aliphatic hydrocarbon radical having l0-20 carbon atoms. and x andy each have a value of from between 1 to 2 so that their sum is 3. The monoethanol ammonium salt mix where R is a C1 C aliphatic hydrocarbon radical is preferred. These compounds are effective in concentrations of at least 0.001 gms./l00 mls. up to 0.02 gms./l00 mls. or more and preferably 0003-0015 gms./l00 mls.

The ammonium salt alkyl esters of phosphoric acid from which the ionic additives of the present invention are selected can be prepared by any of many wellknown techniques. For example, the alkyl esters of orthophosphoric acid can be prepared expeditiously by adding phosphorus pentoxide to an alcohol or mixture of alcohols in mol ratios of 3 to 1 calculated as mols of alcohol to mols of phosphorus pentoxide. In the practice of the invention, straight chain primary alcohols such as decyl, lauryl, myristyl, cetyl, stearyl, cicosyl, and mixtures of these with odd numbered carbon chain alcohols such as undccyl, tridecyl, pentadecyl, heptadecyl, etc., are preferred. in addition, those alcohols having some degree of branching are useful such as tridecyl alcohols made by the Oxo Process.

The additives are usually made by first preparing the mixed mono/dialkyl ester of orthophosphoric acid and thereafter neutralizing the acid with monoethanol amine. While the preferred composition is made by mixing 3 mols of the alcohol with 1 mol of P 0 suitable compositions are prepared by adding either more or less of the alcohol provided that substantially all of the excess phosphoric acid is neutralized with the ethanol amine. Preferred mixtures comprise essentially an equal concentration of monoalkyl diammonium and dialkyl mono ammonium salt. However, it is conceivable that some trialkyl phosphate as well as triammonium phosphate salts are formed in minor amounts. Since mixtures of alcohols are more readily available commercially, their use is preferred. For example, a product of Shell Chemical Company sold under the trademark Neodol-25, percent of which comprises a mixture of alcohols having a straight chain length of from 12 to 15 carbon atoms and 20 percent primary alcohols with an -methyl group with an average molecular weight of 207 for the mixture, provides a highly suitable and preferred source of alcohol. Other such alcohol mixtures sold under the trademarks Alfol 1014 and Alfol 1618 by Continental Oil Company are also useful.

EXAMPLE l lzhosphorylation of Neodol-ZS, 80 percent of which comprises a mixture of straight chain primary alcohols having 12 15 carbon atoms with an average molecular weight of 207, is carried out by adding 648 parts of P 0 to 2,836 parts of alcohol over a period of 2 hours with agitation at a temperature of 30 60 C.

222 parts of the resulting mixture of the acidic partial esters are then combined with 46.2 parts of monoethanol amine with vigorous agitation to form the corresponding mixture of monoethanol amine salts. The product is a light amber paste which when heated to A dispersant composition, readily dispersible in petroleum distillate fuels at high dilution, is then prepared by incorporating the monoethanol amine salt in No. 2

fuel oil, kerosene, or other petroleum distillate products at a concentration of 5 grams per 100 mls. and higher. A stock solution of 5 gms./100 mls. (5% w/v) in No. 2 fuel oil is used as the carrier in the following lit-ISIS.

EXAMPLE 2 A petroleum distillate fuel oil stabilized against the deposition of sludge upon storage is prepared by adding 3 mls. of the stock solution of Example 1 per liter of No. 2 fuel oil to yield a composition containing 0.015 gms. of the mixed monoethanol amine salt per 100 mls. of oil. Higher and lower concentrations from at least 0.001 gms. up to about 0.02 gms. per 100-mls. (0.8 gms./gallon) (l oz./barrel) are made by diluting stock solutions or by adding the mixed salt directly to the fuel oil to be stabilized.

PUMPING TEST The effectiveness of the additives is demonstrated in a test apparatus comprising a reservoir with agitator from which an oil is recycled in series through a water trap, a filter, a pump, and a standard nozzle return outlet. The equipment is also provided with a pressure gauge and means for controlling the pressure in the line. In this apparatus two-gallon portions of untreated No. 2 fuel oil or kerosene are treated with'sufflcient quantities of the dispersant composition stock solution of Example 1 to yield the concentrations indicated in Table I. To the treated oil are then added synthetic sludge designated K-80l provided by the Baltimore Paint and Color Company to adjust the concentration of the oil mix to 0.06 mls. per 99.14 mls. and 66 mls. ofa synthetic rust slurry prepared by separately dissolving 20.32 gms. of ferric chloride-6 hydrate and 16.04 gms. of ferrous chloride-4 hydrate in 600 ml. portions of tap water, mixing these together and adding to this solution 200 mls. of a water solution containing 15.5 gms. of sodium hydroxide, diluting to 2,000 mls. with water and ageing for 1 week. The contents of the reser voir are agitated for 2 minutes during the addition of the sludge and rust slurry.

A felt filter having a permeability for No. 2 fuel oil of 530 :30 mls. per minute under a hydrostatic head of 18 inches is placed in the filter holder. The test is run for a total period of 3 hours with the circulating pump pulling the oil from the reservoir through the filter and back to the reservoir. At the end of 1 hour of circulation and also after 2 hours, the flow through the filter is measured at a hydrostatic head pressure of 18 inches and is compared with the initial flow of clean No. 2 fuel oil. Each time, an additional charge of additive, sludge, and rust slurry equivalent to that used originally is placed in the reservoir as described. After one additional hour of circulation, the flow is again measured at the 18-inch hydrostatic head pressure. The results are expressed in Table I for the several concentrations tested, as percentages of the flow rate of clean No. 2 fuel oil. The results in the table are compared with fuel oil having no additive and equal concentrations of additives available commercially.

TEST FOR EMULSlFICATlON PROPERTIES it is critical in some instances that a sludge dispersant be ineffective in the formation of oil-in-water or waterin-oil emulsions. To demonstrate the desirable water separation properties, the distillate fuel oils containing the above-described additive is tested for water tolerance according to U. S. Federal Test Method Standard No. 791a, Method 3201.5 entitled Emulsion and Method 3251.7 entitled Interaction of Water and Aircraft Fuels as described in Lubricants, Liquid Fuels and Related Methods of Testing. The following test is a modification and combination of these tests and involves vigorous agitation of 150 mls. of the oil containing the additive with mls. of water at 1,500 R.P.M. for 5 minutes at room temperature and thereafter allowing the emulsion to remain undisturbed for a period of 24 hours. After periods of 1, 2, 5, and 24 hours, the water-fuel interface was observed and rated. The clarity of the oil layer was determined by removing the top 20 ml. portion and measuring its light transmission with a Beckman Model B spectrophotometer, using additive fuel as the standard (100% T) and a wave length of 420 mu. These results are recorded in Table 1 and indicate that the additives of this invention do not appreciably emulsify water and at the same time give improved sludge dispersancy.

TABLE I Emulsifieation test Conccn- Pump test, Light tration, percent Interface rating Separation transmission. gms./100 flow 1 (1 hr. percent T Example Additive mls. (3 hrs.) 1 hr. 2 hrs. 5 hrs. 24 hrs. mls. H1O (l-24 hrs.)

Control:

A Untreated fuel 011 No. 2 0 14 B Ashless acrylic polymer having 0.013 76 3 3 3 3 50 93 in. wt. of 50,000. 0.0065 6 0.013 98 2 2 2 .Z 48 93-91 C Barium petroleum su1fonate.... 0.0065 64 0.00% 0.0 96 4 4 4 3 48 35-100 [CH (CH:)io-i:-CH7Oli-5 1 POIONHaCflh-Ofih-s 8%? Si 'IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII Final FlowXlOO 1 Percent flow: m

1 Ratlngl= Clean or clear; lb=A few small bubbles covering 50% of interface and no shreds, lace, or film at interface, 2 Shred of lace and/or film; 3=Loose lace and/or light scum; 4=Tight lace and/0r heavy scum.

What is claimed is:

1. A fuel oil sludge dispersant concentrate which comprises a petroleum distillate having incorporated therein at a concentration of at least 5 grams per 100 mls. a mixture of phosphate salts having the general formula:

(R0) PO (ONH CH CH OH),

(R0), f PO (ONH CH,CH OH),,

wherein R is an aliphatic hydrocarbon radical having 20 carbon atoms; and x arid y are numbers of 1 to 2, the sum of which is equal to 3.

4. A process of claim 3 wherein R is a straight chain hydrocarbon radical of 12 15 carbon atoms and x and y are each about 1.5.

5. A process of claim 3 wherein from 0.0032 to 0.015 gms. of said dispersant are added per 100 mls. of said fuel.

6. A petroleum distillate fuel oil having incorporated therein from 0.001 to 0.02 gms./l00 mls. of said fuel oil of a phosphate salt mixture having the general formula:

(R0), P0 (0NH3CH2CH2OH),

wherein R is an aliphatic hydrocarbon radical having 10 carbon atoms; and x and y are numbers of 1 to 2, the sum of which is equal to 3.

7. A petroleum distillate fuel oil of claim 6 wherein R is an aliphatic hydrocarbon radical having 12 15 carbon atoms, and x and y are each about 1.5.

8. A petroleum distillate fuel oil of claim 6 having incorporated therein from 0.003 to 0.15 gms. of said phosphate salt mix per mls. of said fuel oil. 

2. A dispersant of claim 1 wherein R is a straight chain hydrocarbon radical of 12 - 15 carbon atoms and x and y are each about 1.5.
 3. A process for stabilizing petroleum distillate fuels against the deposition of sludge which comprises adding thereto from 0.001 to 0.02 gms./100 mls. of said fuel of a dispersant having the general formula: (RO)x - PO - (ONH3CH2CH2OH)y wherein R is an aliphatic hydrocarbon radical having 10 - 20 carbon atoms; and x and y are numbers of 1 to 2, the sum of which is equal to
 3. 4. A process of claim 3 wherein R is a straight chain hydrocarbon radical of 12 - 15 carbon atoms and x and y are each about 1.5.
 5. A process of claim 3 wherein from 0.0032 to 0.015 gms. of said dispersant are added per 100 mls. of said fuel.
 6. A petroleum distillate fuel oil having incorporated therein from 0.001 to 0.02 gms./100 mls. of said fuel oil of a phosphate salt mixture having the general formula: (RO)x - PO -(ONH3CH2CH2OH)y wherein R is an aliphatic hydrocarbon radical having 10 - 20 carbon atoms; and x and y are numbers of 1 to 2, the sum of which is equal to
 3. 7. A petroleum distillate fuel oil of claim 6 wherein R is an aliphatic hydrocarbon radical having 12 - 15 carbon atoms, and x and y are each about 1.5.
 8. A petroleum distillate fuel oil of claim 6 having incorporated therein from 0.003 to 0.15 gms. of said phosphate salt mix per 100 mls. of said fuel oil. 